1. Field of the Invention
This invention relates to light dimmers, and more particularly to devices for variably controlling the dimming of traffic lights in accordance with predetermined twilight schedules.
2. Background Art
It is known to use clock timers to control various electrical devices, such as lights, radios, and the like. Such devices typically suffer from the disadvantage of fixed times for turning devices on and off, and of failing to respond to varying requirements without manual supervision.
The use of light sensitive devices for controlling lighting apparatus to operate during times of darkness is known. However, such controls are known to suffer from a disadvantage of reliance on light conditions, so that the apparatus may be turned on during daylight hours, for example, as a result of cloudy atmospheric conditions.
There is no provision made in the prior art, however, for control of power consuming electrical apparatus in a reliable manner, in which electrical power supplied to the apparatus is automatically altered as a function of daylight times yet independently of actual light measurement.